Increasing two-photon fluorescence signals by coherent control

Eric R. Tkaczyk; Augustin Mignot; Jing Yong Ye; Istvan Majoros; James R Baker Jr.; Theodore B. Norris

doi:10.1117/12.644979

23 February 2006 Increasing two-photon fluorescence signals by coherent control

Eric R. Tkaczyk, Augustin Mignot, Jing Yong Ye, Istvan Majoros, James R Baker Jr., Theodore B. Norris

Proceedings Volume 6089, Multiphoton Microscopy in the Biomedical Sciences VI; 608910 (2006) https://doi.org/10.1117/12.644979
Event: SPIE BiOS, 2006, San Jose, California, United States

Abstract

Two-photon excitation fluorescence of complex solvated molecules (Rhodamine590, Fluorescein, and G5-dendrimer conjugated Fluorescein) was successfully controlled using adaptive pulse shaping. We were able to maximize and minimize the ratio of fluorescent yield to average incident power or second-harmonic generation (SHG) in a thin optical crystal. The optimal excitation pulse shape was found experimentally using a genetic learning algorithm and no a priori knowledge. Pulses were shaped with an acousto-optic programmable dispersive filter (Dazzler AOPDF) controlling phase and amplitude of 20 individual frequency components. Convergence occurred over the order of 100 generations of experiments from an original set of 50 random individual pulses. Femtosecond laser pulses (~75 fs, 76 MHz repetition, 800 nm center wavelength, 3nJ without shaping) selected to maximize fluorescence yield / SHG were found to be complementary to those minimizing this ratio when visualized with a SHG-frequency resolved optical gating (SHG-FROG) device. At these powers, linear chirp of the pulse was far less significant in establishing coherent control than the more complex pulse shape. Regeneratively amplified pulses (~150 fs, 20 kHz repetition, 795 nm center wavelength, 2 μJ before shaping) were selected for maximum efficiency of fluorescent yield relative to incident power. The peak intensity, as determined by SHG, did not change significantly for optimal pulses when compared to early generations. This indicates that the improved two-photon fluorescent signal was not the result of simple convergence to a transform limited pulse, and suggests that the dye molecule excited state population is being coherently controlled. We are currently investigating the application of this result to enhancing signal in flow-cytometry and improved discrimination for multi-photon microscopy.

Citation Download Citation

Eric R. Tkaczyk, Augustin Mignot, Jing Yong Ye, Istvan Majoros, James R Baker Jr., and Theodore B. Norris "Increasing two-photon fluorescence signals by coherent control", Proc. SPIE 6089, Multiphoton Microscopy in the Biomedical Sciences VI, 608910 (23 February 2006); https://doi.org/10.1117/12.644979

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available